In previous design of a fusion reactor, an economically attractive commercial reactor has been adopted, and R& D issues for realizing a fusion reactor economically competitive with existing other energy resources such as fission reactor and fossil fuel have been nominated. Therefore, many kinds of R & D are now promoted in the fields of plasma physics and fusion technology. While, the research and development for these issues takes long time and are very expensive. Sometimes, it is said that these R & D issues should be also incorporated into DEMO reactor, although the main purpose of DEMO is to establish the engineering feasibility of fusion reactor.While, the urgent realization of a fusion reactor is also expected from the viewpoint of environmental problems, since a fusion energy has a high quality compared with other energy resources (fossil, solar and so on). Here based on presently-available and highly-reliable scientific knowledges, we have proposed a new strategy for early realization of fusion reactor, and designed an inductively-operated pulsed tokamak fusion reactor (called IDLT reactor). The IDLT-DEMO reactor has a major radius of 10 m, a fusion power of 800 MW and an operation period of 4 hours, and austenite materials such as 316 SS could be available. This would result in the early realization of the fusion reactor as an electric power plant, although IDLT reactors are relatively large compared with other attractive reactors.核融合炉の実現を大きく左右している因子として、プラズマ閉じ込めの改善、ダイバータプラズマ制御等のプラズマ物理的要素と、高中性子壁負荷材料や高磁場コイルの開発等の炉工学的要素が挙げられる。これら因子に対して現在までに得られた知見及び達成された技術を基礎としてデモ炉を設計すると、装置主半径10m、核融合出力800MW、運転時間4時間と比較的大型装置とならざるをえない。しかしこのデモ炉では、オーステナイト系の材料が使え、十分高い稼動率も確保でき、発電用デモ炉としての要件はすべて具備しており、20〜30年後の早期実現が可能である。